1. Field of the Invention
The present invention relates to a projection type video display such as a liquid crystal projector.
2. Description of the Background Art
Conventionally, a liquid crystal display so adapted that display luminance and contrast are made constant even when the APL (Average Picture Level) of a video is changed (see JP-A-08-201812), or a projection type video display for reducing lamp driving power when the APL of a video is high, while increasing lamp driving power when it is low, to improve contrast (see JP-A-03-179886) has been proposed.